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-rw-r--r--kernel/printk/Makefile1
-rw-r--r--kernel/printk/index.c195
-rw-r--r--kernel/printk/internal.h8
-rw-r--r--kernel/printk/printk.c74
4 files changed, 229 insertions, 49 deletions
diff --git a/kernel/printk/Makefile b/kernel/printk/Makefile
index eee3dc9b60a9..d118739874c0 100644
--- a/kernel/printk/Makefile
+++ b/kernel/printk/Makefile
@@ -3,3 +3,4 @@ obj-y = printk.o
obj-$(CONFIG_PRINTK) += printk_safe.o
obj-$(CONFIG_A11Y_BRAILLE_CONSOLE) += braille.o
obj-$(CONFIG_PRINTK) += printk_ringbuffer.o
+obj-$(CONFIG_PRINTK_INDEX) += index.o
diff --git a/kernel/printk/index.c b/kernel/printk/index.c
new file mode 100644
index 000000000000..d3709408debe
--- /dev/null
+++ b/kernel/printk/index.c
@@ -0,0 +1,195 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Userspace indexing of printk formats
+ */
+
+#include <linux/debugfs.h>
+#include <linux/module.h>
+#include <linux/printk.h>
+#include <linux/slab.h>
+#include <linux/string_helpers.h>
+
+#include "internal.h"
+
+extern struct pi_entry *__start_printk_index[];
+extern struct pi_entry *__stop_printk_index[];
+
+/* The base dir for module formats, typically debugfs/printk/index/ */
+static struct dentry *dfs_index;
+
+static struct pi_entry *pi_get_entry(const struct module *mod, loff_t pos)
+{
+ struct pi_entry **entries;
+ unsigned int nr_entries;
+
+#ifdef CONFIG_MODULES
+ if (mod) {
+ entries = mod->printk_index_start;
+ nr_entries = mod->printk_index_size;
+ }
+#endif
+
+ if (!mod) {
+ /* vmlinux, comes from linker symbols */
+ entries = __start_printk_index;
+ nr_entries = __stop_printk_index - __start_printk_index;
+ }
+
+ if (pos >= nr_entries)
+ return NULL;
+
+ return entries[pos];
+}
+
+static void *pi_next(struct seq_file *s, void *v, loff_t *pos)
+{
+ const struct module *mod = s->file->f_inode->i_private;
+ struct pi_entry *entry = pi_get_entry(mod, *pos);
+
+ (*pos)++;
+
+ return entry;
+}
+
+static void *pi_start(struct seq_file *s, loff_t *pos)
+{
+ /*
+ * Make show() print the header line. Do not update *pos because
+ * pi_next() still has to return the entry at index 0 later.
+ */
+ if (*pos == 0)
+ return SEQ_START_TOKEN;
+
+ return pi_next(s, NULL, pos);
+}
+
+/*
+ * We need both ESCAPE_ANY and explicit characters from ESCAPE_SPECIAL in @only
+ * because otherwise ESCAPE_NAP will cause double quotes and backslashes to be
+ * ignored for quoting.
+ */
+#define seq_escape_printf_format(s, src) \
+ seq_escape_str(s, src, ESCAPE_ANY | ESCAPE_NAP | ESCAPE_APPEND, "\"\\")
+
+static int pi_show(struct seq_file *s, void *v)
+{
+ const struct pi_entry *entry = v;
+ int level = LOGLEVEL_DEFAULT;
+ enum printk_info_flags flags = 0;
+ u16 prefix_len = 0;
+
+ if (v == SEQ_START_TOKEN) {
+ seq_puts(s, "# <level/flags> filename:line function \"format\"\n");
+ return 0;
+ }
+
+ if (!entry->fmt)
+ return 0;
+
+ if (entry->level)
+ printk_parse_prefix(entry->level, &level, &flags);
+ else
+ prefix_len = printk_parse_prefix(entry->fmt, &level, &flags);
+
+
+ if (flags & LOG_CONT) {
+ /*
+ * LOGLEVEL_DEFAULT here means "use the same level as the
+ * message we're continuing from", not the default message
+ * loglevel, so don't display it as such.
+ */
+ if (level == LOGLEVEL_DEFAULT)
+ seq_puts(s, "<c>");
+ else
+ seq_printf(s, "<%d,c>", level);
+ } else
+ seq_printf(s, "<%d>", level);
+
+ seq_printf(s, " %s:%d %s \"", entry->file, entry->line, entry->func);
+ if (entry->subsys_fmt_prefix)
+ seq_escape_printf_format(s, entry->subsys_fmt_prefix);
+ seq_escape_printf_format(s, entry->fmt + prefix_len);
+ seq_puts(s, "\"\n");
+
+ return 0;
+}
+
+static void pi_stop(struct seq_file *p, void *v) { }
+
+static const struct seq_operations dfs_index_sops = {
+ .start = pi_start,
+ .next = pi_next,
+ .show = pi_show,
+ .stop = pi_stop,
+};
+
+DEFINE_SEQ_ATTRIBUTE(dfs_index);
+
+#ifdef CONFIG_MODULES
+static const char *pi_get_module_name(struct module *mod)
+{
+ return mod ? mod->name : "vmlinux";
+}
+#else
+static const char *pi_get_module_name(struct module *mod)
+{
+ return "vmlinux";
+}
+#endif
+
+static void pi_create_file(struct module *mod)
+{
+ debugfs_create_file(pi_get_module_name(mod), 0444, dfs_index,
+ mod, &dfs_index_fops);
+}
+
+#ifdef CONFIG_MODULES
+static void pi_remove_file(struct module *mod)
+{
+ debugfs_remove(debugfs_lookup(pi_get_module_name(mod), dfs_index));
+}
+
+static int pi_module_notify(struct notifier_block *nb, unsigned long op,
+ void *data)
+{
+ struct module *mod = data;
+
+ switch (op) {
+ case MODULE_STATE_COMING:
+ pi_create_file(mod);
+ break;
+ case MODULE_STATE_GOING:
+ pi_remove_file(mod);
+ break;
+ default: /* we don't care about other module states */
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block module_printk_fmts_nb = {
+ .notifier_call = pi_module_notify,
+};
+
+static void __init pi_setup_module_notifier(void)
+{
+ register_module_notifier(&module_printk_fmts_nb);
+}
+#else
+static inline void __init pi_setup_module_notifier(void) { }
+#endif
+
+static int __init pi_init(void)
+{
+ struct dentry *dfs_root = debugfs_create_dir("printk", NULL);
+
+ dfs_index = debugfs_create_dir("index", dfs_root);
+ pi_setup_module_notifier();
+ pi_create_file(NULL);
+
+ return 0;
+}
+
+/* debugfs comes up on core and must be initialised first */
+postcore_initcall(pi_init);
diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h
index 51615c909b2f..1596e2837318 100644
--- a/kernel/printk/internal.h
+++ b/kernel/printk/internal.h
@@ -12,6 +12,12 @@
#define PRINTK_NMI_CONTEXT_OFFSET 0x010000000
+/* Flags for a single printk record. */
+enum printk_info_flags {
+ LOG_NEWLINE = 2, /* text ended with a newline */
+ LOG_CONT = 8, /* text is a fragment of a continuation line */
+};
+
__printf(4, 0)
int vprintk_store(int facility, int level,
const struct dev_printk_info *dev_info,
@@ -51,6 +57,8 @@ bool printk_percpu_data_ready(void);
void defer_console_output(void);
+u16 printk_parse_prefix(const char *text, int *level,
+ enum printk_info_flags *flags);
#else
/*
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index a6b94c3c5ac5..87b8e7c81368 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -350,11 +350,6 @@ static int console_msg_format = MSG_FORMAT_DEFAULT;
* non-prinatable characters are escaped in the "\xff" notation.
*/
-enum log_flags {
- LOG_NEWLINE = 2, /* text ended with a newline */
- LOG_CONT = 8, /* text is a fragment of a continuation line */
-};
-
/* syslog_lock protects syslog_* variables and write access to clear_seq. */
static DEFINE_RAW_SPINLOCK(syslog_lock);
@@ -1961,23 +1956,24 @@ static inline u32 printk_caller_id(void)
}
/**
- * parse_prefix - Parse level and control flags.
+ * printk_parse_prefix - Parse level and control flags.
*
* @text: The terminated text message.
* @level: A pointer to the current level value, will be updated.
- * @lflags: A pointer to the current log flags, will be updated.
+ * @flags: A pointer to the current printk_info flags, will be updated.
*
* @level may be NULL if the caller is not interested in the parsed value.
* Otherwise the variable pointed to by @level must be set to
* LOGLEVEL_DEFAULT in order to be updated with the parsed value.
*
- * @lflags may be NULL if the caller is not interested in the parsed value.
- * Otherwise the variable pointed to by @lflags will be OR'd with the parsed
+ * @flags may be NULL if the caller is not interested in the parsed value.
+ * Otherwise the variable pointed to by @flags will be OR'd with the parsed
* value.
*
* Return: The length of the parsed level and control flags.
*/
-static u16 parse_prefix(char *text, int *level, enum log_flags *lflags)
+u16 printk_parse_prefix(const char *text, int *level,
+ enum printk_info_flags *flags)
{
u16 prefix_len = 0;
int kern_level;
@@ -1993,8 +1989,8 @@ static u16 parse_prefix(char *text, int *level, enum log_flags *lflags)
*level = kern_level - '0';
break;
case 'c': /* KERN_CONT */
- if (lflags)
- *lflags |= LOG_CONT;
+ if (flags)
+ *flags |= LOG_CONT;
}
prefix_len += 2;
@@ -2004,8 +2000,9 @@ static u16 parse_prefix(char *text, int *level, enum log_flags *lflags)
return prefix_len;
}
-static u16 printk_sprint(char *text, u16 size, int facility, enum log_flags *lflags,
- const char *fmt, va_list args)
+static u16 printk_sprint(char *text, u16 size, int facility,
+ enum printk_info_flags *flags, const char *fmt,
+ va_list args)
{
u16 text_len;
@@ -2014,14 +2011,14 @@ static u16 printk_sprint(char *text, u16 size, int facility, enum log_flags *lfl
/* Mark and strip a trailing newline. */
if (text_len && text[text_len - 1] == '\n') {
text_len--;
- *lflags |= LOG_NEWLINE;
+ *flags |= LOG_NEWLINE;
}
/* Strip log level and control flags. */
if (facility == 0) {
u16 prefix_len;
- prefix_len = parse_prefix(text, NULL, NULL);
+ prefix_len = printk_parse_prefix(text, NULL, NULL);
if (prefix_len) {
text_len -= prefix_len;
memmove(text, text + prefix_len, text_len);
@@ -2038,7 +2035,7 @@ int vprintk_store(int facility, int level,
{
const u32 caller_id = printk_caller_id();
struct prb_reserved_entry e;
- enum log_flags lflags = 0;
+ enum printk_info_flags flags = 0;
struct printk_record r;
u16 trunc_msg_len = 0;
char prefix_buf[8];
@@ -2070,22 +2067,22 @@ int vprintk_store(int facility, int level,
/* Extract log level or control flags. */
if (facility == 0)
- parse_prefix(&prefix_buf[0], &level, &lflags);
+ printk_parse_prefix(&prefix_buf[0], &level, &flags);
if (level == LOGLEVEL_DEFAULT)
level = default_message_loglevel;
if (dev_info)
- lflags |= LOG_NEWLINE;
+ flags |= LOG_NEWLINE;
- if (lflags & LOG_CONT) {
+ if (flags & LOG_CONT) {
prb_rec_init_wr(&r, reserve_size);
if (prb_reserve_in_last(&e, prb, &r, caller_id, LOG_LINE_MAX)) {
text_len = printk_sprint(&r.text_buf[r.info->text_len], reserve_size,
- facility, &lflags, fmt, args);
+ facility, &flags, fmt, args);
r.info->text_len += text_len;
- if (lflags & LOG_NEWLINE) {
+ if (flags & LOG_NEWLINE) {
r.info->flags |= LOG_NEWLINE;
prb_final_commit(&e);
} else {
@@ -2112,20 +2109,20 @@ int vprintk_store(int facility, int level,
}
/* fill message */
- text_len = printk_sprint(&r.text_buf[0], reserve_size, facility, &lflags, fmt, args);
+ text_len = printk_sprint(&r.text_buf[0], reserve_size, facility, &flags, fmt, args);
if (trunc_msg_len)
memcpy(&r.text_buf[text_len], trunc_msg, trunc_msg_len);
r.info->text_len = text_len + trunc_msg_len;
r.info->facility = facility;
r.info->level = level & 7;
- r.info->flags = lflags & 0x1f;
+ r.info->flags = flags & 0x1f;
r.info->ts_nsec = ts_nsec;
r.info->caller_id = caller_id;
if (dev_info)
memcpy(&r.info->dev_info, dev_info, sizeof(r.info->dev_info));
/* A message without a trailing newline can be continued. */
- if (!(lflags & LOG_NEWLINE))
+ if (!(flags & LOG_NEWLINE))
prb_commit(&e);
else
prb_final_commit(&e);
@@ -2186,28 +2183,7 @@ int vprintk_default(const char *fmt, va_list args)
}
EXPORT_SYMBOL_GPL(vprintk_default);
-/**
- * printk - print a kernel message
- * @fmt: format string
- *
- * This is printk(). It can be called from any context. We want it to work.
- *
- * We try to grab the console_lock. If we succeed, it's easy - we log the
- * output and call the console drivers. If we fail to get the semaphore, we
- * place the output into the log buffer and return. The current holder of
- * the console_sem will notice the new output in console_unlock(); and will
- * send it to the consoles before releasing the lock.
- *
- * One effect of this deferred printing is that code which calls printk() and
- * then changes console_loglevel may break. This is because console_loglevel
- * is inspected when the actual printing occurs.
- *
- * See also:
- * printf(3)
- *
- * See the vsnprintf() documentation for format string extensions over C99.
- */
-asmlinkage __visible int printk(const char *fmt, ...)
+asmlinkage __visible int _printk(const char *fmt, ...)
{
va_list args;
int r;
@@ -2218,7 +2194,7 @@ asmlinkage __visible int printk(const char *fmt, ...)
return r;
}
-EXPORT_SYMBOL(printk);
+EXPORT_SYMBOL(_printk);
#else /* CONFIG_PRINTK */
@@ -3215,7 +3191,7 @@ int vprintk_deferred(const char *fmt, va_list args)
return r;
}
-int printk_deferred(const char *fmt, ...)
+int _printk_deferred(const char *fmt, ...)
{
va_list args;
int r;
generated by cgit (git 2.34.1) at 2024-06-10 06:51:01 +0000